Comic books can be a difficult to get into, what with their years of serial storytelling and convoluted continuity. Luckily, there are plenty of one-and-done graphic novels out there. Here are some of the best four-color gateway drugs.

In picking these books, I tried to avoid picking from the über-obvious (Watchmen) and those books about familiar superheroes (Dark Knight Returns). We love ourselves some capes here at io9, but the medium goes beyond up, up, and away. Also, I wanted to keep the selection affordable, self-contained, and accessible — you should be able to find all of these books at a fair price online. And with these stand-alone stories, all you need is one hit.

Orbiter by Warren Ellis and Colleen Doran (2003)
In the near future, Kennedy Space Center has been abandoned after the Space Shuttle Venture disappeared in orbit. 10 years later, the Venture returns to Kennedy...covered in organic skin. What happened to the crew? For a Warren Ellis book, Orbiter is surprisingly devoid of scatologically florid insults, chain-smoking protagonists, and threatened eviscerations. It's also one of his more hopeful books and offers an extraterrestrial tale tinged with — dare I say? — humanism.

Black Hole by Charles Burns (finally compiled in 2005)
Burns' graphic novel took a decade to finish, but it was worth it. In the suburbs of Seattle, teenagers who are infected with a mutagenic STD are exiled to the woods. We don't know where "The Bug" came from, but we do know that growing up sucks a lot more when you sprout an extra mouth on your throat. Burns will be back in October with his Tintin-inspired X'ed Out. Speaking of which...

Tintin in Tibet by Hergé (1958)
The Tintin series dabbled in science fiction — Flight 714 tackled ancient astronauts, The Calculus Affair featured superweapons, and this book stars an antagonist most abominable. But antagonist is too harsh of a word, as the book has no villain. In this adventure, Tintin searches for his old friend Chang, whose plane has crashed in the Himalayas. Easily the most beautiful Tintin book in both visuals and narrative, Tintin in Tibet is a rumination on loneliness, sacrifice, and the power of hope against a merciless frozen backdrop. It's the most mature and accessible Tintin tale by far, and the story's barely contingent on the boy reporter's prior adventures.

Heavy Liquid by Paul Pope (1999)
Somewhere in late 21st century New York City, a man named "S" is pouring a mysterious metal into his ear canal. This metal isn't on the Periodic Table, but it gives you one helluva buzz...and that man in the Picasso mask is one of several dodgy characters who wants it. Paul Pope builds a future that's not much different from our own, barring the 30-minute transatlantic flights and defense robots. Pope's artwork makes the tale all the more believable — he depicts the shadows and creases of reality like no one else in comicdom.

Marvel Boy by Grant Morrison and J.G. Jones (2000)Marvel Boy is a superhero comic that remixes 1960s Marvel tropes with Grant Morrison's best high concept weirdness. Gamma-powered super-soldiers! Living corporations! Mind-control saliva! You don't need to know anything about the Kree Empire, S.H.I.E.L.D., or the Marvel Universe whatsoever to appreciate James Bond-esque evil billionaires in Iron Man armor. The titular Marvel Boy is a fixture of the 616 Universe nowadays, but his modern appearances have almost nothing to do with this shimmering pop collage.

Ronin by Frank Miller and Lynn Varley (1983)Ronin doesn't get the love of other Frank Miller books, which is a pity. The movie's been in development hell for a while now, but no matter. This graphic novel about an ancient samurai loose in dystopian New York City evokes both the grittiness of 1980s comics and a future where human evolution's gone haywire.

Enigma by Peter Milligan and Duncan Fegredo (1993)
One of the earliest titles from DC's Vertigo line, Enigma is one of Peter Milligan's finest works. Murderous supervillains from Michael Smith's childhood comics are coming to life. Who's doing this? What control does the comic's author have over these characters? And what does this have to do with Michael's sexuality? This oddly sweet book is filled with enough metatextual metahumans to satisfy any Vertigo aficionado.

I Kill Giants by Joe Kelly and J. M. Ken Niimura (2008)
Barbara Thorson is a D&D loving fifth grader who makes some rather bold claims about her titan-slaying abilities. This doesn't endear her to her classmates, but when elements of her fantasy begin to pervade the real world, Thorson must make good on her boasts. This here's a trippy and charming coming-of-age fable.

What are your favorites graphic novels to foist upon your hapless pals? Sound off in the comments!